Editing Leptospirosis (section)

===Laboratory tests===
For those who are infected, a [[complete blood count]] may show a [[Leukocytosis|high white cell count]] and a low platelet count. When a [[Anaemia|low haemoglobin count]] is present together with a [[Leukopenia|low white cell count]] and [[thrombocytopenia]], [[bone marrow suppression]] should be considered.<ref name="Haake 2015"/> [[Erythrocyte sedimentation rate]] and [[C-reactive protein]] may also be elevated.<ref name="Lane 2016"/>

The kidneys are commonly involved in leptospirosis. Blood [[urea]] and [[creatinine]] levels will be elevated. Leptospirosis increases potassium excretion in urine, which leads to a [[Hypokalemia|low potassium level]]<ref name="Haake 2015"/> and a [[Hyponatremia|low sodium level]] in the blood.<ref name="Lane 2016"/><ref name="Haake 2015"/> Urinalysis may reveal the [[Proteinuria|presence of protein]], [[Pyuria|white blood cells]], and microscopic [[haematuria]].<ref name="Lane 2016"/> Because the bacteria settle in the kidneys, urine cultures will be positive for leptospirosis starting after the second week of illness until 30 days of infection.<ref name="Lane 2016"/>

For those with liver involvement, [[transaminase]]s and direct bilirubin are elevated in [[liver function test]]s. The Icterohaemorrhagiae serogroup is associated with jaundice and elevated bilirubin levels. [[Hemolytic anemia]] contributes to jaundice. A feature of leptospirosis is acute [[haemolytic anaemia]] and [[Conjugation (biochemistry)|conjugated]] hyperbilirubinemia, especially in patients with [[glucose-6-phosphate dehydrogenase deficiency]].<ref name="Haake 2015"/> Abnormal [[Serum (blood)|serum]] [[amylase]] and lipase levels (associated with pancreatitis) are found in those who are admitted to hospital due to leptospirosis. Impaired kidney function with [[creatinine clearance]] less than 50 ml/min is associated with elevated pancreatic enzymes.<ref name="Haake 2015"/>

For those with severe headache who show signs of meningitis, a [[lumbar puncture]] can be attempted. If infected, [[cerebrospinal fluid]] (CSF) examination shows [[Lymphocyte|lymphocytic]] predominance with a cell count of about&nbsp;500/mm<sup>3</sup>, protein between&nbsp;50 and 100&nbsp;mg/ml and normal glucose levels. These findings are consistent with [[aseptic meningitis]].<ref name="Haake 2015"/>

====Serological tests====
Rapid detection of ''Leptospira'' can be done by quantifying the IgM antibodies using [[ELISA]]. Typically, ''L. biflexa'' antigen is used to detect the IgM antibodies. This test can quickly determine the diagnosis and help in early treatment. However, the test specificity depends upon the type of antigen used and the presence of antibodies from previous infections. The presence of other diseases such as [[Epstein-Barr virus]] infection, viral [[hepatitis]], and [[cytomegalovirus]] infection can cause false-positive results.<ref name="Haake 2015"/> Other rapid screening tests have been developed such as dipsticks, [[Latex fixation test|latex]] and slide agglutination tests.<ref name="Lane 2016"/>

The microscopic agglutination test (MAT) is the reference test for the diagnosis of leptospirosis.<ref name="Haake 2015"/> MAT is a test where serial dilutions of patient sera are mixed with different serovars of ''Leptospira''. The mixture is then examined under a [[Dark field microscopy|dark field microscope]] to look for [[Agglutination (biology)|agglutination]]. The highest dilution where 50%&nbsp;agglutination occurs is the result.<ref name="Haake 2015"/> MAT [[Titer|titres]] of 1:100 to 1:800 are diagnostic of leptospirosis.<ref name="Lane 2016"/> A fourfold or greater rise in titre of two sera taken at symptoms' onset and three to 10&nbsp;days of disease onset confirms the diagnosis. During the acute phase of the disease, MAT is not specific in detecting a serotype of ''Leptospira'' because of cross-reactivity between the serovars.<ref name="Haake 2015"/> In the [[convalescent]] phase, MAT is more specific in detecting the serovar types.<ref name="Haake 2015"/> MAT requires a panel of live antigens and requires laborious work.<ref name="Bennett 2015"/>

====Molecular tests====
''Leptospira'' DNA can be amplified by using [[polymerase chain reaction]] (PCR) from serum, urine, [[aqueous humour]], CSF, and autopsy specimens.<ref name="Haake 2015"/> PCR can detect ''Leptospira'' DNA in blood even before the antibody response develops. As PCR detects the presence of ''Leptospira'' DNA, it is useful even after antibiotic treatment has started.<ref name="Lane 2016"/>